1. Field of the Invention
The present invention relates to an ink jet recording apparatus and more particularly to an information processing apparatus such as a computer, an electronic typewriter, a word processor, a facsimile equipment, a copying machine or the like which empoys said ink jet recording apparatus as an output terminal for, for example, images, characters.
2. Related Background Art
Various types of recording systems for recording on a recording medium (referred to "recording paper" or simply to "paper", hereinafter) such as paper, sheets for OHP, etc. have been conventionally proposed on which recording heads operated by varied kinds of recording systems are mounted. The recording heads may be types of wire dot system, thermosensitive system, thermal transfer system ink jet system, etc.
Particular attention recording head has been paid to ink jet system as used in, since this recording system has such advantages that ink is ejected directly to the recording paper, running cost thereof is low and a recording action is quiet.
In recent years, the ink jet recording apparatus, more specifically, the recording head, has been manufactured according to film formation technique or micronization technique in a semiconductor device, and therefore, the production of a more compact and more inexpensive recording head has been realized. Thus, for example, a replaceable recording head integrated with an ink tank has been proposed and the miniaturized and simple structure of an apparatus itself has been enabled, under the circumstances.
The ink jet recording apparatus having the various advantages as mentioned above has been widely utilized as a recording apparatus for varied devices including an electronic typewriter, a word processor, a facsimile equipment, a copying machine, etc. In this case, the ink jet recording apparatus must have a structure which meets functions, and conditions for employment inherent to these devices.
As for the electronic typewriter, the word processor or the like, a compact, light and portable type is liable to be liked, and therefore, the ink jet recording apparatus used for these devices must have been compact and simple in this point.
In the ink jet recording apparatus of such type, a recording operation is performed in such a way that ink is supplied to a recording head, the ink is ejected from an ejection outlet provided on the face of the recording head opposed to a recording medium to form flying ink droplets and the ink droplet is applied to the recording medium. In the ink recording apparatus, generally, during the recording operation or when the recording head is not used but is kept standing or the like, ink scum, paper powder or dust may possibly adhere to an ink ejection outlet or air bubbles may enter the interior of the ink ejection outlet, which causes an ink discharge failure. These causes of the ink discharge failure have been removed by using recovery methods such as the ink being sucked out of the ink ejection outlet, the ink being discharged from the ejection outlet by pressing an ink supply system, or the ink being removed by performing a prescribed ink discharging operation (called "preliminary discharge" or "idle discharge"), in place of these forced discharging operations, or along with them.
The above described ink jet recording apparatus has operated in response to the automatic operation of the above recover device or a manual operation thereof by an operator when the power of the recording apparatus is turned on, when recording failure is generated during the recording, after a long recording interruption or after a prescribed amount of recording operation.
However, in such an ink jet recording apparatus that the recover device is designed to operate when the power is turned on or during the interruption of the recording operation, irrespective of whether the recording is performed thereafter or not, and therefore, the ink is unavoidably wastefully thrown away according to a discharge stabilizing process (recover process). Especially, in recent years, the use of recording heads of a type that the ink is discharged by making use of thermal energy enables the miniaturization of the ink jet recording apparatus to be promoted. Some ink jet recording apparatuses, as one example of use, may be integrally built in a word processor, an electronic typewriter and other information processing apparatus. In such a recording apparatus, since the power is often turned on for example, only for editing sentences without performing the recording, increase in the amount of ink consumed in the ink jet recording apparatus causes a great problem.
In case where the recover process is performed in response to a manual operation according to the decision of the operator, the recording medium on which the recording failure arises is inevitably wasteful because the recover device operates after the failure in recording is detected.
Further, even if the prescribed number of similar recover operations are automatically carried out when a predetermined stand-by period elapses, the discharge failure including non-discharge may not be completely recovered only depending on the prescribed number of recover operation, in case where, for example, the recording head is left as long as more than one month, because prescribed time and the number of recover operations are constant. For instance, in case the recording head has been left as long as 26 hours, the prescribed number of recover operations are conducted, which may, on the contrary, lead to the excessive increase of the recover operations and to the wasteful consumption of the ink due to the suction of ink or the like.
In case the recover operation is conducted when the power is turned on and then, the recording head is left with the power kept turned on without performing the recording operation, there is a possibility that the recovery operation is not carried out during an ordinary recording, resulting in the discharge failure including non-discharge. In the control for performing the recover operation every time the power is turned on without taking time from the recovery process of the preceding time into consideration, the recover operation is performed every power on, in case the power is repeatedly turned on and off at intervals of short time, which inconveniently results in an unnecessary recovery operation.